Previous fixed dose studies of glipizide GITS, an oral hypoglycemic agent for the treatment of type II diabetes mellitus, have demonstrated that no dose-response relationship exists between glycated hemoglobin and doses of GITS ranging from 5-60mg. Conversely, a dose-response relationship was observed with fasting plasma glucose and doses ranging from 5 - 20mg. However, the duration of treatment at assigned doses was limited to 8 weeks. New data from the literature has indicated that decreases in glycated hemoglobin lag significantly behind decreases in fasting plasma glucose and the appropriate time interval to observe stable glycated hemoglobin levels is 4 months. Therefore, the current study will assess the effect of titration of GITS at 4 month intervals. Since glipizide GITS is now commercially available as Glucotrol XL, the likelihood of future studies with this medication is significantly reduced.